This invention relates to a drop wire clamp assembly which is used to support an insulated drop wire relative to a structure such as a pole or building.
Typically, a drop wire clamp assembly is used to support an insulated telephone cable which is strung between a pole and a building. The drop wire clamp assembly has a wire loop which attach to the structure so as to take the strain off of the connection where the telephone line reaches the building or telephone pole. The clamp assembly should firmly grip and hold the drop wire even under maximum tension. However, the grip must be made without breaking or cutting the insulation, which would eventually cause failure of the telephone service.
A typical drop wire clamp assembly comprises a wedge shaped bail housing having a series of ridges, and a wedge slide which mates with the bail housing to locate the insulated telephone drop wire therebetween. The wedge slide has a wire loop extending therefrom for connection to the structure. The bail housing and wedge slide are often formed of stainless steel or other metal. A shim or pressure pad having a large number of perforations is located between the wedge slide and the insulated drop wire, and has retaining ears which prevent the shim from moving longitudinally. As the wedge slide is slid through the bail housing, the shim presses into the insulation of the telephone line to firmly grip and hold the telephone line.
While the above-described drop wire clamp assembly produces the desired result of firmly gripping drop wires even under maximum tension, and is relatively inexpensive to manufacture, it has a number of serious defects in practice. The line installer needs to place the telephone drop line within the bail housing, then place the shim over the line, and while holding together this structure, insert and pull the wedge slide into position. The wire loop is then connected onto a hook or other connection to the structure. In the process of performing all of these operations, the shim may fall out, or may not be properly oriented against the insulated telephone drop wire. The presence of the shim is a cause of many practical difficulties during installation. However, when the shim is omitted or drops out, gaps in the bottom surface of the wedge slide as it is pulled into the bail housing can cut into the insulated drop wire and create an undesirable break in the insulation.
Other types of drop wire clamp assemblies have been utilized over the years. For example, it has been known to provide an assembly in which the shim is eliminated by forming an insert with a pair of side walls with cast-in teeth which are deformable against the insulated wire to thereby clamp the drop wire. This type of assembly is not as convenient, and has not been accepted in the trade to the extent of the first mentioned drop wire clamp assembly.